lsnet is a system monitor that generates detailed
charts for viewing on your Web site. One pixel
represents 1 minute. It displays data for one day and also has a daily network usage chart showing how much up/down traffic there was for each day of the month.

Chev is a sane by default vulnerability check script that checks NIST and US Cert RSS feeds for a short list of software that you configure. It has two levels of priority, warn and critical, which allows for easy use with Nagios as a stand-alone script or in a cron job. Just add strings for your major pieces of software and chev will tell you when a vulnerability has been released.

ColorLogs is an output-colorizing Perl script intended to have command output piped through it to a terminal. It allows easy creation of new highlighting configurations using simple text matches, globs, or regular expressions. It works transparently even in interactive contexts with scripts that produce prompt lines and wait for user input. Patterns are provided for Ant and Maven output. This version started as a fork of v1.1 from resentment.org, but numerous improvements have been made since then.

Guardog is a simple but powerful intrusion dectection system (IDS) that works by inspecting messages from log files, network packets, and other sources. It uses Perl regular expressions to check for any bad messages.

Devilish is an application for monitoring log files in real time. It uses inotify to detect log file modifications. When an appended line has a string you are interested in, it will alert you via your notification daemon and with an icon in the tray.

zLogFabric is an all in one cross-platform logging solution that collects log lines/messages over a messaging system to a central server instance. The modular design enables the server to store, forward, alert, and generate live statistics out of the logged data.
It can collect log information from files, syslog, log4j, log4net, and Windows event logs.

nxlog is a modular, multi-threaded, high-performance log management solution with multi-platform support. In concept, it is similar to syslog-ng or rsyslog, but is not limited to Unix/syslog only. It can collect logs from files in various formats, receive logs from the network remotely over UDP, TCP, or TLS/SSL on all supported platforms. It supports platform-specific sources such as the Windows Eventlog, Linux kernel logs, Android device logs, local syslog, etc. Writing and reading logs to/from databases is also supported for many database servers. The collected logs can be stored into files, databases, or forwarded to a remote log server using various protocols. The old BSD Syslog and the newer IETF syslog standard (RFC 3164 and RFC 5424-5426) are fully supported by nxlog in addition to XML, JSON, CSV, GELF, and other custom formats. A key concept in nxlog is to be able to handle and preserve structured logs so there is no need to convert everything to syslog and then parse these logs again at the other side. It has powerful message filtering, log rewrite, and conversion capabilities. Using a lightweight, modular, and multi-threaded architecture which can scale, nxlog can process hundreds of thousands of events per second.

danotation is a simple language and tool for processing small databases, primarily collections of logs maintained by hand. Unlike most other data languages and formats, it aims primarily to be used with a text editor by a human user rather than produced with a computer program.